Abstract
Purpose:
Low macular pigment optical density (MPOD) has previously been demonstrated in patients with glaucoma. This study was designed to investigate the MPOD response to oral dietary macular pigment (MP) supplementation in glaucoma patients.
Methods:
Eighty-eight subjects with glaucoma were recruited into the Macular Pigment and Glaucoma Trial (ISRCTN56985060), a placebo-controlled, double-masked and randomized clinical trial. Subjects were assigned with equal probability to placebo (n = 44) or treatment arms (n = 44), which comprised a daily oral supplement containing 10mg lutein, 2mg zeaxanthin and 10mg meso-zeaxanthin for a period of 6 months. All subjects underwent a series of vision-related tests including the measurement of MPOD at 0.25, 0.50 and 1.00 degrees of retinal eccentricity using customized heterochromatic flicker photometry. Fourier-domain optical coherence tomography was performed to analyze the ganglion cell complex (GCC), which was used to stratify subjects into those with foveal involvement versus those without. All data were collected at baseline and at 6 months.
Results:
Eighty-three subjects (44 male, 39 female); mean age (±SD), 65 (10), range 36-84 years completed the trial. At final visit, central MPOD increased significantly in the treatment arm. Mean MPOD (SD) at 0.25 degrees of retinal eccentricity was 0.25(0.12) at baseline vs 0.30(0.12) at follow up (p=0.01); and 0.21(0.10) vs 0.25(0.10) at 0.50 degrees of retinal eccentricity (p=0.003). There was no statistically significant response in the placebo arm (p>0.05 for all eccentricities). Within the intervention group, a significant MPOD response was observed across both the fovea-involved and fovea-not-involved groups.
Conclusions:
MPOD can be increased in glaucoma patients with oral MP supplementation. The level of MPOD increase, however, was small relative to increases previously reported among normal and age-related macular degeneration subjects. There may be a potential role of MP replacement therapy in glaucoma, but would require a supplementation study over a longer duration.